LIBRPRY OF CONGRESS 



015 870 917 ft 






TS 1630 

S6 
Copy 1 



MTED STATES DEPARTMENT OF AGRICULTURE 



mm. BULLETIN No. 1100 | 




&J* ^~ru 



Washington, D. C. 



September, 1922 



A METHOD OF DETERMINING 

IN WOOL. 



GREASE AND DIRT 



By D? A. Spencer, Senior Animal Husbandman in Shee/i^ind Goat Investigations, 
J. I. Hardy, 1 Sheep Husbandman, and Mary J. Brandon, Scientific Assistant 
in Sheep and Goat Investigations, Animal Husbandry Division, Bureau of Animal 
Industry. 



CONTENTS 

P;il'.' 



Object of this investigation 1 

Method of obtaining data 1 

Experimental work 2 

Index figures for grease and dirt 2 

Basis of the index figures 5 

Conditioning for weighing 6 



Experimental work. — Continued. Page. 

Determining weight of grease 11 

Determining weight of dirt 15 

Weekly working schedule 15 

E xplanation of wool-scouring data sheet . 19 

Summary 20 



OBJECT OF THIS INVESTIGATION. 

The object of the wool-scouring' investigation here discussed is to 
afford a fair basis for comparing the grease and dirt indices of va- 
rious wools, the indices to be used to divide wools into groups for the 
study of other qualities affected by or associated with grease and 
dirt contents, such as length of fiber, fineness, densit}* of fleece, spin- 
ning qualitj^, strength, and weight of clean wool per fleece. Data 
obtained are to be used in planning the mating of the sheep that 
grow the fleeces studied for the purpose of fleece improvement in 
the qualities mentioned. 

METHOD OF OBTAINING DATA. 

Sheep-breeding investigations conducted by the Bureau of Ani- 
mal Industry, United States Department of Agriculture, involve 
extensive studies in fleece improvement. Individual fleeces of 
about 2.000 sheep are studied each year, and the problem of obtaining 
data on the net yield of clean wool from each fleece has prompted 
the development of a method of single-fleece determination that 
would yield dependable results without necessitating the complete 

1 Moisture experiments reported in this bulletin were conducted by J. I. Hardy during the winter of 
1919 and 1920. Doctor Hardy resigned from the department in February, 1920. 
111962— 22— Bull. 1100 1 



fa 2- 



2 



BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE. 



scouring of all the wool. Separate, determinations of the grease and 
dirt content of each fleece furnish information of great usefulness for 
sheep-breeding studies in connection with their application to wool 
improvement, but the expense of separate determinations for so 
large a number of fleeces creates the necessity for working with 
samples instead of. scouring entire fleeces. A sample weighing 
approximately 1 pound is therefore taken from the side of each 
fleece at the time the sheep are sheared. These samples are then 
sent direct to the Bureau of Animal Industry wool laboratory, near 
Beltsville, Md., and stored in a dry room until they are used in the 




Fig. 1.— Wool containers, balance, and record book. The closed container shows the can of raw wool 
ready for shipping and storing at the wool laboratory, Beltsville, Md. Upon preparing the wool for 
scouring, the container is opened and the wool is placed in the basket shown on the balance. A sample 
sheet of the data kept in the record book is shown in Table 7. 

scouring test. Most of the fleeces studied to date have been grown 
on the bureau's experimental range sheep at the United States sheep 
experiment station, near Dubois, Idaho, although fleeces grown at 
the bureau's farm sheep stations near Beltsville, Md., and Middle- 
bury, Vt., are also being sampled for use in this investigation. 

EXPERIMENTAL WORK. 

INDEX FIGURES FOR GREASE AND DIRT. 

Specially designed apparatus has been constructed to remove the 
grease by the use of gasoline, without loss of dirt, and later in another 
apparatus the wool is washed to remove all the dirt. 

Approximately 250 grams of each sample of wool as it comes 
from the storage room are used for the scouring test. The sam- 



UBMrtr 6F CONQr1l88 

*se«ivso 
SFP30i9g2 

DOCUMSNTf* 6IV|0I@N 



Ttb\&3o 



DETERMIXIXG GREASE AXD DIRT IX T WOOL. 



pies are placed in wire-mesh baskets (see Fig. 1) and brought to 
a constant-moisture content 3 by drying in an oven. After heating 
at 50° C. for three hours in this conditioning oven they are weighed 
with a delicate balance. (See Fig. 2.) 

The samples are then placed in extraction containers and washed 
with deodorized gasoline (gas-engine gasoline) such as is used in 
canning factories. After the gasoline is put on the samples they 
are agitated up and down in the container 10 times and are allowed 
to stand for 45 minutes, after which the gasoline is allowed to filter 
through 13-inch filter papers. After all the gasoline is filtered, 




Fin. 2.— Conditioning oven. Xote method of weighing woo] baskets without opening glass oven door. 
Baskets are brought into position for weighing by turning the wheel shown below and in front of the 
oven. When in position the basket is hooked on to the weighing apparatus. 

the filter paper containing the dirt is folded and placed with the 
sample. Clean filter papers are then placed under the extrac- 
tion containers, and a second gasoline washing is given the wool 
samples. The same filter papers are used for the second and third 
extractions. After three gasoline extractions the remaining filter 
papers are also placed with their respective samples and the wool is 
again brought to air-dry condition. (See Figs. 3 and 4.) When it 
is necessary to save time the samples are placed in a blower-dryer 
to speed up this operation. (See A, Fig. 4, also C, D, and E, Fig. 5.) 
Drying for one hour in the blower-dryer and standing in the open at 
room temperature for 15 minutes brings the samples to an air-dry 

■ "Constant-moisture content," as used here, allows for a slight variation but is insufficient to affect 
the results appreciably. 






> 



i,u-h 



4 BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE. 

condition. The samples are again dried, at 50° C. for three hours, 
and weighed. 

The samples are next washed with soap and water at a tempera- 
ture of from 40° to 45° C. for three-quarters of an hour. (See Fig. 
5.) About one-half pound of neutral soap is placed in the first vat 
containing 150 gallons of water. After washing the samples, the 
water is squeezed from them and they are placed in a second vat 
and washed for half an hour in clear water at a temperature of from 
40° to 45° C. When washing extremely dirty wool, one-quarter of 
a pound of neutral soap is added to the 150 gallons of water in t he 







Fig. 3. — Grease extraction apparatus. Extraction containers are shown in the right half of this illus- 
tration, with filter papers beneath. The baskets of wool are placed in these containers and gasoline is 
poured into the containers until within 2 inches of the top Lids are placed on the containers after the 
agitating process, and the gasoline is allowed to stand 45 minutes. I'pon filtering, the gasoline returns 
to the pressure tank, A. It is then forced into the distillation tank, B, condensed in tank, C, and re- 
turned through the collecting tank, I>. and the upper pipes into can, E. At F is shown the card file 
bearing the weekly schedule of work. A card is used for each day's program. This schedule is show n 
in full on page 17. 

second vat and the wool is again washed for 30 minutes, but soap 
is not used in the second vat unless the wool is extremely dirty. 
In case soap has been used in the second vat the water is squeezed 
from the wool and it is washed a third time in clear water at the 
same temperature. After the samples have been washed in one 
clear water for 30 minutes the water is squeezed from them by the 
use of a wringer; they are put into the original containers and dried 
in the blower-dryer at 60° C. for eight hours, allowed to stand over- 
night, and conditioned in the conditioning oven for three hours. 
The weight of the grease is found by the difference in the weight of 
conditioned, greasy wool and the conditioned weight of the sample 
after three washings with gasoline. Likewise the weight of the dirt 
is found bv the difference in the weight of the conditioned wool 



DETERMINING GREASE AND DIRT IX WOOL. 5 

after washing with gasoline and the weight of the same conditioned 
wool after washing with soap and water. 

BASIS OF THE INDEX FIGURES. 

A difference in dirt content of raw wool would cause a difference 
in the percentage weight of grease and clean wool in samples that 




Fig. 4. — Degreased wool airing after three treatments of gasoline. The two large cans in the foreground 
are shown collecting the gasoline returned from the gasoline still in the rear. Air pipe. A, connects lower 
and upper parts of blower dryer used for drying wool after trashing. 

are similar except that one is of lower dirt content than the other. 
Likewise, a difference in grease content would cause a realignment 
of percentage figures. In order, therefore, to obtain a fair and 
constant basis for indices of grease and dirt, the actual weight of 
each of these materials removed is considered in its relation to the 



6 BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE. 

final weight of clean wool found in the sample. For example, the 
grease index is calculated by the following formula: 
100 X weight of grease 
weight of clean wool 

CONDITIONING FOR WEIGHING. 

The foregoing outline shows the need of three weighings of each 
sample. It often happens that different classes of wools may be . 
handled at the same time and similar wools may be worked with 
on days varying widely as to temperature and moisture. In order 
to get useful data from the determinations made throughout the 
year and with different wools, it is necessary to condition the wools 
for each weighing in such way as to overcome the effect upon the 
results of differences in natural moisture or of moisture contents as 
affected by varying air conditions. Two samples of wool might 
contain quite different quantities of moisture, due to their contents 
of grease and foreign matter. The index figures would be based 
upon final weight of clean wool. This index might be rendered in- 
correct to the extent of 0.03 per cent in case conditioning was not 
sufficient to bring these samples to a uniform moisture content, for 
example : 

Sample A under natural conditions in air contains — ■ 

Grams. 

Moisture 15 

Grease 20 

Dirt 40 

* lean wool 25 

Total weight 100 

Sample B has similar amounts of grease and clean wool, but 45 
per cent of its weight in dirt and only 10 per cent moisture. The 
true composition is then as follows: 

Grams. 

Moisture 10 

Grease 20 

Dirt 45 

I 'lean wool 25 

Total weight 100 

Results of tests shown in Table 2-c indicate that imperfect condi- 
tioning might remove 60 per cent of the moisture from sample A 
and only 50 per cent from sample B. Calculation of the grease index 
on this basis would therefore result as follows : 

Sample A, 60 per cent of 15 grams moisture removed equals 9 
grams, leaving a remainder of 6 grams. 

Grams. 

Moisture 6 

Grease 20 

Dirt 40 

Clean wool 25 

Total weight of conditioned sample 91 



DETERMINING GKEASE AND DIKT IX WOOL. 7 

One hundred grams of such conditioned wool would have: 

Grams. 

100 X 6 
Moisture — jp[ — = 6. o9 

100X20_ 
Grease — <pj — =21.98 

100X40 ,„ .„ 
Dirt £— =43. 96 

100X25 
( lean wool — gr — =-■ 4' 

Total 100 

,_„ 21.98 (grams of grease) „_ „, • , 

100 x- _ ... , j— t^ i =80. 01, grease index. 

27. 4^ (grams of clean wool) 

Sample B, 50 per cent of 10 grams moisture removed equals 5 
grams, leaving a remainder of 5 grams. 

Grams. 

Moisture o 

Grease 20 

Dirt 15 

< lean wool 25 

Total weight of conditioned wool 95 

One hundred grams of such conditioned wool would have — 

Grams. 
Moisture — 05 — = 5. 26 

100X20 
Grease — gg — =21. 05 

100X45 ,. „_ 
Dirt — 95— =47. 3i 

< lean wool — pg — =26. 32 

Total 100 

,-_ 21.05 (grams of grease) _. -.„ • , 

100 X ng 00 }* f , & St = 79. 98, grease index. 

26. 32 (grams of clean wool) 

Even though there is a difference of 5 per cent in the moisture of 
sample A as compared-with sample B, the grease index is not changed 
appreciably, the difference here shown being 80.01-79.98 = 0.03. 

Table 1 shows results from nine samples, A-l to A-9. The air-dry 
weights of these samples were taken on a comparatively dry day and 
conditioned for three hours at 50° C. These same samples were ex- 
posed in a moist room and again conditioned for three hours at 50° C. 
They are designated in the table as B-l to B-9. All weights are given 
in terms of grams. 



BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE. 



Table 1. — Comparison of effects of dry weather 


and wet weather on conditioning of wool. 




A. 


B. 


Diflerenee between 
conditioned weights 


Sample. 


Dry-day 

air 
weight. 


After 

3 hours 

at 50° C. 


Wet-day 

air 
weight. 


After 
3 hours 
at 50° C. 


A and B. 

Per cent based on 

conditioned "A" 

samples. 


1 


Grams. 
272.5 
272. 8 
271.1 
27.3. 3 
274.0 
303.0 
272.0 
269.7 
277.5 


Grams. 
263.5 
262.0 
259.7 
262.8 
262.3 
291.1 
262.5 
259.1 
266.0 


Grams. 
284.9 
283.4 


Grams. 
266.2 
263.2 


Grams. 
2.7 
1.2 


Per cent. 
1.01 


2 


.45 


3 


_NJ. ii 261.6 1.9 
283. 9 : 264. 9 2. 1 


.72 


4 


.79 


5 


282.6 261.3 
311.8 i 291.3 
282. 7 1 263. 5 
278. 5 , 259. 2 
286. 8 266. 6 


-1.0 
0.2 

1.0 
0.1 
0.6 


- .38 


6 


.06 


7 


.38 


8 


.038 


9 


.22 











There is a maximum difference of 2.7 grams, or 1.01 per cent, in the 
moisture, of samples A and B after three hours' conditioning. Accord- 
ing to calculations of grease indices for samples A and B, which are 
shown just preceding Table 1, this difference is not large enough 
to affect seriously the figures for grease index. 

Table 2 shows the results of conditioning wool for different lengths 
of time and gives comparisons of the effect of conditioning wool at 50° 
C.as compared with conditioning at 100° C. Comparison of the weights 
of samples after four hours' drying at 100° C. with the weights of the 
same samples after five hours' drying at 100° C. shows that 
the extra hour resulted in a very small loss in weight. It is, 
therefore, assumed that the weight of the samples after five hours' 
drying at 100° C. shows the lowest weight that may be obtained by 
driving off moisture. In other words, weights of the samples after 
heating five hours at 100° C. are considered moisture-free, and the 
difference between these weights and the original air-dry weights rep- 
resents the moisture contained in the air-dry samples, and this figure 
is used as the basis for calculating the percentage of moisture lost. 

Table 2. — Eesults of conditioning wool samples, 
a. WEIGHTS OF WOOL SAMPLES. 



Grade of sample. 



Idaho fine medium.. 

Delaine 

Do 

Idaho fine medium, 
very dirtv 

Do....: 



Sample 
No. 



Air-dry. 



Grams. 
207.9 
152.1 
203.1 

211.7 
212. 



Dried at 50° C 



Dried at 100° C 



End 
first 
hour. 



Grams. 
196.3 
143.5 
193.7 

199.6 
199.6 



End 
second 
hour. 



Grams. 
190.7 
140. 5 
187.5 

195.1 
195.0 



End 


End 


End 


third 


third 


fourth 


hour. 


hour. 


hour. 


Grams. 


Grams. 


Grams. 


188.0 


174.96 


170. 7S 


139.2 


133. 63 


132. 17 


187.7 


180.16 


177. 54 


192.5 


177. 52 


176. 57 


192.6 


180.52 


179. 12 



End 
fifth 
hour. 



Grams. 
168. 10 
131.15 
175. 61 

174.47 
177. 49 



6. WEIGHT OF MOISTURE LOST. 



Idaho fine medium . . 


10 
11 
12 

15 
17 


207.9 
152.1 
203.1 

211.7 
212.0 


11.6 
8.6 
9.4 

12.1 
12.4 


17.2 
11.6 
15.5 

16.6 
17.0 


19.9 
12.9 
15.4 

19.2 
19.4 


32.94 
18. 47 
22.94 

34.18 
31.48 


37.12 

l'l.lti 

25.56 

35.13 

32.88 


39.8 
20.95 


Do 


27.49 


Idaho fine medium, 


37.23 


Do 


34.51 







DETERMINING GREASE AND DIRT IX WOOL. 

Table 2. — Results of cmiditioning wool samples — Continued, 
c. PER CENT OF MOISTURE LOST. 





Sample 
No. 


Dried at 50° 


C. 


Dried at 100" 


c. 


Grade of sample. 


End 
first 
hour. 


End 
second 
hour. 


End 
third 
hour. 


End 

tlurd 
hour. 


End 
fourth 
hour. 


End 

fifth 
hour. 




10 
11 
12 
15 
17 


Pt r ci nt. 
29. 15 
41.05 
14 19 
32. 50 
93 


I't r cent, 
1X22 

55. 37 

56. 38 
44.59 

19. 26 


Per cent. 
50.00 
61.58 
56.02 
51.57 
56. 21 


Per cent. 

82. 76 
88.16 

83. 44 
91.81 
91.22 


Per cent. 
93. 27 
95. 13 
92.97 
94.36 
95. 2S 


Per cent. 
100 




100 


Do.... 


100 


Idaho tine medium, very dirtv.. . 

Do ;...." 


100 
100 







Table 2-c shows that conditioning for three hours at 50° C. re- 
moved from 50 per cent to 61.5 per cent of the moisture contained in 
the air-dry wool tested. The calculations previously shown for the 
theoretical cases of samples A and B are therefore in line with actual 
tests shown in Table 2. These results, therefore, form the basis for 
the decision that conditioning wool samples at 50° C. for three hours 
is sufficient to permit scouring experiments to be conducted within 
reasonable limits of error. As sufficient accuracy is possible by con- 
ditioning at 50° C. for three hours while moisture-free conditioning 
would require a great deal more trime and expense, all samples used 
in the wool laboratory ..tests at Beltsville, Md., are conditioned for 
three hours at 50° C. 

The same samples as were used for the tests reported in Table 1 
were also dried at 80° C. and records kept of the percentages of loss in 
moisture at the end of each hour for a period of three hours. All 
percentages in regard to the less-moist samples are based on the air- 
dry weights of the less-moist samples, and all percentages in regard 
to the more-moist samples are based on the air-dry weights of the 
more-moist samples. The results of this experiment are given in 
Table 3. 



Table 3. — Wool samples with different amounts of moisture, weighed at end of each hour 
while drying for a period of three hours at 80° C. 



Sample. 



$1 
?! 
3 3 



as ! b~ 

S3.2P g „ 

© © 

§•5 13 

«•- I ot'S 



0.S 



w S3 

03 '5 

06 

*a 



asa 



5^- 

<& Or- 






'ft a 



g 2 






a 



,* Is-* 3 



i3§ 






o c.9 

a 



- z -~ 3 'Si 

s^ 1 ai 



S3 



.23 1 si 



a 3 



o-. 

a 



9t"j 



*J r* <V 

2 S fc - 



gS.a 



2B-9 2 
ft 1 
§ 3-° 
3.2™ 

— ■3 
7 .23 

ess 



Gins. 

1 267.3 

2 267.7 

3 269.6 



4 

5. 

6... 

7... 

8... 

9... 



Average.. 



269.2 
267. 8 
267. 2 
265. 9 
268 I 

269. 3 



Gms. 
285. 4 
282.5 
284.1 
282. 7 
283 6 
282. 6 
281.0 
282 3 
2S4.0 



Gms. 

257. 7 

255.3 

259.3 

260. 

25' 

255.5 

253. 5 

257.5 

257.4 



Gms. 
268.7 
267.1 
269. 2 
26S.3 
266.8 
264.3 
262.9 
266.1 



P. Ct. 
3. 59 
3.51 

3. 82 
3.41 

3. 84 
4.37 

4. 66 
1 23 
4.41 



P.ct 
5. 85 

5. 45 

5 24 
5 09 

5. 92 

6.47 
6.44 

5.73 

6. 40 



Gms 

251.7 

252 7 

2.74 

254.6 

252.1 

249. 5 

248.9 

252. 

252.3 



Gms 

260.7 

26H.2 

262. 4 

201.7 

259 5 

256.2 

255. 6 

259.5 

259.1 



P.ct 
5.8 
5.60 
5.52 
5.42 
5. 
6.62 
6.39 
6 112 
6.31 



P.ct 
S.65 
7 
7.63 
7.43 
8.49 
9.34 
904 
8.07 
s. 77 



268. 1 2-3.13 257.41 



266-57 



3- 98 5. ■ 



259.4 



5.95 



Gms. 

248. 4 
249.7 
251.8 
251.6 

249. 3 
246.7 
245.7 
250 B 
249.1 



Gms 

277 7 
27,7. .7 
277. 5 
257.2 
254.9 
252.0 
250.8 
255.4 
254 



P.ct. 
7.07 
6.72 
6.60 
6.53 
6.90 
7.67 
7.59 
6.73 
7.50 



P.ct. 
9.71 
9.56 
9.25 
9.02 
10.12 
10.82 
10.74 
9.52 
10.31 



S. 37 249. 23 



255. 11 



7.03 



111962— 22— Bull. 1100- 



10 



BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE. 



An analysis of Table 3 shows that the more-moist samples, air-dry, 
averaged 15.03 grams heavier than the same samples of wool when 
less moist and air dry, while the more-moist samples averaged only 
5.88 grams heavier than the less-moist samples after conditioning 
three hours at 80° C. In other words, the average difference in weight 
due to moisture content was reduced by conditioning three hours at 
80° C. to 39.1 per cent of the original difference between the more- 
moist samples air dry and the less-moist u re samples air dry. It 
will also be noted that the more-moist samples consistently lost 
more moisture each hour during the conditioning process than was 
lost from the less-moist samples. 

In like manner the same samples as were used in the tests reported 
in Table 3 were used to study the effects of conditioning at 50° C. 
The samples were weighed air-dry and dried at 50° C. for three hours 
and weighed at the end of each hour. The same samples were then 
allowed to take on more moisture and weighed again in a similar 
manner. All percentages in regard to both the less-moist and more- 
moist samples are based on the air-dry weight. 

Table 4. — Wool samples, with different amounts of moisture, weighed ni thi <"<l of each 
hour while drying for a period of thret hours at 50 C 



Sample. 



] 

2.... 

■J 

4 

5 

6 

7 

8 

9... 

Average 



p. • 

C3 ac 



272 :. 
272. 8 
271.1 

271.11 

303 
272.0 
269. 7 

277 



271. 2 






284.9 
283. 1 
2S2.II 
283.9 

2v2 ii 
Ills 
282.7 
278. :. 

2S6. x 



286 28 



— - 

Si 



J* 



Cms 
267. 4 

263. 7 

2r,i; 9 



IS 



o * 

£2 

I* 



271 2 
271.7 
27(1. :( 
27.1. 4 



266.5 270. I 



295. 4 
266 2 
262. 6 

211! I. 9 



271.6 

267. 3 
275.3 



269. 4 27.'.. 6! 2. 16 






; aS 



i- *- o 

5£.£ 



p. a. 

1 s7 

2 I I 

2. 73 
2 24 
2. 

2. :.i 
2. i.; 
2. 63 

2 7; 



»-.5 

3 • 



£3 



'3« 

££ 



p. a. 
3 75 

1 12 
4.14 
3 69 
1 II 
l . 76 
3.92 
I 02 
I. m 



S3 

71 — 



3 = 



263. :i 

'i.i 

264.3 
26 I. 7 
212. 4 
263. 5 
260.0 
2H7. II 



269 i 

jm, ; 
2rt4. 8 
267. 
264 2 

2.14 

2i.li I 

262 ii 
269 3 






- ^ o 

s S5 



o — = 



P.et. 

2.93 
3. 18 
3. 65 
3.29 
3.75 
3. 49 
:?. 12 
:i. 59 
3.78 



P. cl. 

5 17 

6 ii ; 
6.09 
5.70 

ii. :.l 
5 :.i 

;.. 7i 

:,. 92 
6.10 



72 j.ii. i. 269 18 I 15 5.90 205 .:.: 2i.i'.. :,; ::.93 6.90 



p.2 

£1 



21,.:. 5 
262.0 
2.".' i 7 
262. 8 
2'. I. I 
291 . I 
21.2. 5 
259. 1 
266.0 



— s a ; 

C ™ (- c . . 



/ r "- 
..- © = 

c ^ — 






3 — c 



-;.7..v 
2i.i.. 2 
2.. 1. 2 
2i,l i. 
21'. 1.9 
21.2. 2 
291.3 
263.5 
259. 2 
266. i'. 



/'. <■/. 
1.30 
3.95 

4 21 
3.84 

I i,. 

:i. 49 
3.93 
1.14 



/' et. 
6.56 
7.13 

7. 2:i 
1, I,', 
7.18 
6. 57 

1, 79 

I, 92 
7.114 



The weights presented in Table 4 show that the more-moist sam- 
ples, air-dry, averaged 10.08 grams heavier than when they were less 
moist but air dry. After conditioning for three hours at 50° C. 
there was an average difference of only 1.2 grams between the more- 
moist and less-moist samples. The conditioning for three hours at 
50° C, therefore, resulted in reducing the difference in weight due 
to moisture so that at the end of the three hours the average differ- 
ence was only 11.9 per rent as great as it was before conditioning. 
The final difference in the case of sample 8 was only 0.1 gram, which 
was the smallest difference found in this test, while the greatest 



DETERMINING GREASE AND DIRT IN WOOL. 11 

final difference was 2.7 grams in the case of sample 1. Using the 
air-dry weights of the less-moist samples as the basis for percentages, 
this difference of 2.7 grams amounts to only 0.99 per cent of the air- 
dry weight of the original sample, and the average difference of 1.2 
grams is only 0.43 per cent of the average air-dry weight of the less- 
moist samples, while the smallest difference of 0.1 gram in the case 
of sample 8 amounts to only 0.037 per cent, all of which are negligible. 
In view of the fact that these experiments showed no advantage 
in conditioning wool at a higher temperature, it was decided to con- 
dition samples at 50° G. The object is to obtain a basic or "condi- 
tional" weight, and on the basis of these experiments, 50° C. for three 
hours seemed to offer this condition when there is no more than 20 
per cent of moisture in the air-dry samples. In the experiments here 
reported, 20 per cent moisture was the largest percentage for any of 
the samples used. Results of these experiments prove that the dry- 
ing of wool samples containing no more than the usual amount of mois- 
ture for three hours at 50° C. is sufficient to remove all excess of 
moisture that would cause an appreciable error in the determination 
of grease, dirt, and clean-wool contents of raw wool. 

DETERMINING WEIGHT OF GREASE. 

The preceding discussion shows that in order to bring the samples 
to a constant-moisture content it is necessary to condition them 
three times before each of the three weighings in the process. It is 
equally important that all the grease be removed between the first 
and second conditionings in order to obtain the grease content 
distinct from the dirt. 

The results of tests, involving a scries of gasoline treatments on 
20 Rambouillet and 20 crossbred 3 fleece samples (in which was shown 
the percentage of grease removed by each gasoline extraction until 
free from grease), form the basis for other tests to determine the 
exact number of treatments necessary to remove all grease. Table 5 
shows the results from the 20 Rambouillet and the 20 crossbred 
wool samples. 

> The crossbred sheep used in this investigation are the result of matin? Rambouillet ewes with rams 
of coarse-wool breeds, and the interbreeding of such crosses; also sheep of the Corriedale breed. 



12 



BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE. 



Table 5. — Grease removed by a series of gasoline treatments, conditioning between treat- 
ments. 

RAMBOUILLET FLEECE SAMPLES. 



























.a 
s ■ 

*1 
•g* 

a S 
o ce 
■3 ** 

a 


Cumulative weight 
of grease removed 
at each treatment 
-(grams). 


Cumulative per cent 
of grease removed 
at each treatment. 


SZ w £. 


- -r ■' 


2c 
£ a <" 
£v a 

•a a 


Per cent total 

grease rem oved 

at— i 


Sample No. 












a o S 

>- s " 








+3 


1 

CO 


•a 

a 

3 


g 


■Si 


a 
o 
o 


■6 

t- 

3 


.a 

H 

a 
o 




■6 
a 
o 


1 




u 


H 


N 


u 


CO 


e 


N 


Dh 


a. 


tu 


PH 


CO 


e« 


2779 


234. 7 


40.3 


46.9 


49. 1 


49.9 


17.17 19.98 


20.92 


21-21 


2. vl 


0.94 


0.34 


SO. 76 


93.98 


98.39 


2826 






230. 1 


36.2 


42.7 


44.7 


44.7 


15.73 16 55 


19.42 


19.42 


2.S2 


.87 


.OC 


vii.: iv 


'.I5. .',2 


100.00 


2936 






233. S 


24.0 


28.1 


30. 3 


30. 3 


10.27 12.03 


12.97 


12.97 


1.76 


.94 


.oc 


79.21 


92. 73 


100.00 


2968 






234.2 


36.6 


41.5 


43.6 


44.1! 


15.62 17.71 


18*61 


lv 7v 


2. OS 


.9C 


.17 


83.18:94.31 


99.09 


2411 






222.0 

232 'J 


28.5 
49.6 


32.3 
56.8 


33.3 
59.4 


34.1 
59. 5 


12.83 14.54 

21.29,24.38 


15.0 

2:,. :,l 


1 5. 3' 
25. 54 


1.71 
3.09 


.46 
1.12 


.36 

.04 


S3. 57|94. 72 
S3. 36195.46 


97.65 


2474 






99.83 


2698 






232. 1 


35.0 


40. S 


42. 9 


43.2 


1 5. 46 1 17. .".7 18.48 


IS. fil 


2.11 


.91 


. 13 S3. 1 Hi. 44 


99.31 


3137 






231.6 


28.8 


33. 7 


35. 7 


35. t 


12.43 14.55 


15. 41 


15.5 


2.12 


.86 


.09 80.2283.87 99.44 


2136 






237 v 

m 4 


37. 7 
38.2 


42. 9 
44.4 


44.7 
46.5 


44.7 
46.8 


15.85 18.04 

16. 72119. 43 


Iv 79 
20. 35 


lv 7! 
20.49 


2.19 
2.71 


.75 
.92 


.00!S4. 34:95.97 


100.00 


2147 






.14 


SI. 62 


94.87 


99.35 


2151 






.,.,., , 


33.3 


38.6 


39. 4 


39. 5 


14.3216.61 


16.95 


i«. m 


2.29 


.34 


.04 


S4.3 


97.72 


99.74 


2747 






■"'34 o 


31.4 


36.4 


38. 3 


38. 4 


13.3815.51 16.32 


16.36 


2.13 


.81 .04 


SI. 77 


94.79 


99.73 


1656 




...1229.1 


32. 3 


37.3 


39. 1 


838. 7 


14 if 16.28 17 .">■ 


216. 8S 


2. 19 


7v 2- .17 


v3. 46 


in] 3s 


2101 .03 


1779 




. . . 239. 3 


43. 5 


49.6 


51.4 


51.7 


18.17 20.7221.47 


21.6 


2.55 


.75 


.13 


S4.13 


95. 93 


99.41 


1824 




. . . 236. 3 


36. 7 


42.4 


44.5 


44.5 


15.53 17.94 lv B3 


IS. S3 


2.41 


.89 


.00 


S2. 47 


95. 28 


100.00 


1875 




... 218.3 


27.2 


31.5 


33. 6 


233.2 


12 15 11 4245.39 


215. 21 


1.97 


.97 


2- .18 


81.92 


94. S7 


2101.20 


1216 




. . . 235. 1 


34. 5 


39.9 


41.2 


M0. !) 


14.(77 l(i.97 17.52 


217.3S 


2.30 


.55 


2- .13 


84. 35 


97.55 


2100 73 


1240 




. . . 22S. s 


33. 3 


37.8 


39.5 


39.fi 


14.5516.52l7.2i. 


17.31 


1.97 


.74 


.05 


S4.09 


95. 45 


99.74 


1251 




... 229.0 


32. 5 


37.4 


39. 2 


39.2 


14. 19 10. 33,17. 11 


17.11 


2.14 


.78 


.00 


.82. 91 


'1,. II 


100.00 


12S4 






»7 4 


37.3 


41.8 


43.5 


243.0 15. 


218. 11 


1.9 


.71 


2- .21 


86. 74 


97.21 


2101.16 
















Average 






231.9 


34.9 


40.1 


42.0 


42.1 


15.04 


17.31 


18.11 


lv I.", 


2.27 


.80 


.04 


82.89 


95.36 


99.77 



CROSSBRED FLEECE SAMPLES. 



A-227.... 

A-2S7.... 
A-364.... 
A-440.... 
B-742.... 
B-799.... 
B-887.... 
Lcn. 211. 
Lcn. 244. 
Lcn. 460. 
Lcn. 511. 
i la. :«:... 
Cla. 101.. 
Cla. 112.. 
Cts. 63. . . 
C-260.... 
D-1SS... 
E-211.... 

0-94 

U. S. 168. 



Average... 



. 240. 2 
. 247. 4 
. 244. 3 
. 240. 
. 240. 7 
. 239. 6 
. 239.9 
. 242. 
. 238. 
. 249. 2 
. 2111. 1 

236 6 

.239.8 
.241.0 
.241.2 
. :243. 5 

243 7 
.241.2 

245.0 
. 24S. 6 



31.. 8 33 

35.7 38.3 

31.6 33.9 

29.3 31.3 

26.5 27.4 

2v ;, m, i 

25.3 2; 

38 v 14 2 

29.1 31.4 

26.5 2H.2 

21.1 22.4 

25.9 27.2 

I ! 

25.3 29.0 



17.9 
18.7 

24.3 
29.8 

42.11 
43.6 



29.3 



19.5 

20. 

27.2 

:-;2.i 
45.7 
47. S 



32.li 



37.5 
41.9 
37. 6 
36. 5 
31.8 
35.2 
32.4 
46. 4 
35.6 
33.7 

21,. I: 

31.3 
44.1 
33.2 
21.0 

24.6 
30.4 
36 2 
19.8 
50.9 



37.6 

42.6 
38. I 
36.6 
32.4 
35.6 
32 6 
47.6 
36 2 
34.0 
27 2 

32, 1 
45. 7 
35.1 
23. 6 
25. 2 
30. 
36.6 
50.3 
51. S 



36.6 



23 1 1 
43 15. 

93 13. 
91 12. 

HI II 
89 12. 

5-1 11. 

it: is. 

22 13. 
63 11. 
78 9. 

94 11. 
5510. 
4912. 
42 8, 
(.7 v 
97 11. 

35 13 

1 1 |v. 

53 19. 



II i;,. 15 
4v [6.93 
15.39 
14.83 
13.21 
14.69 
13.51 
19. 17 
I I 9:, 

; J 
11.07 
13 22 

iv ;i9 
13.77 
v .71 
111. 10 
12.47 
17, 111 
20. 32 
20. 47 



14.7S 



15. 65 
17.21 
17, 71 

I 1.87 
13.46 
14. 85 
13.58 
19.66 
17, 21 
13. (14 

II 32 
13. 56 
19.05 
14.56 

9.78 
10.34 
12. 67 
17,. 17 
20.53 
20.83 



15.10 



ll vv 

1.05 
.94 
.81 
.37 

1. 
.92 

2.23 
.97 

1.08 
.54 

1. 

1.54 
.66 
.S3 
1.19 
1.16 
1.51 
1.69 



1.10 



1.04 
1.45 
1.52 
2.11 
1.83 
1.72 
2.05 

.91 
1.76 
l.vl 
1.77, 
1.73 
1.90 
1.74 

. 63 
1.60 
1.31 
1.50 
1 67 
1.25 



1.7.9 



0.50 
.28 
.32 
.04 
.25 
.16 
.07 
.49 
.26 
.12 
.25 
.34 
.66 
.79 

1.07 
.24 
.20 
.16 
.21 
.36 



.32 



9(1 17, 
89. 91 
vv. 28 
85.51 

S4..-.I: 

87.35 
84. 35 
92. 85 
86. 74 
88 

7,7 v2 35 
68184. 73 
36 86. 21 
07 82.62 
v l 32 ' 2 



14 
S.8. 02 
89.07 
90.85 

92. 27 



87. 37 



99.73 
98.35 
97.91 
99.72 
98.14 
98.87 
99.38 
97.47 
98.34 
99.11 
97.79 
97.51 
96.49 
94.58 
88.98 
97.61 
98.38 
98.91 
99.01 
98.26 



97.89 



1 In calculating the percentage of grease in the last three columns the amount of grease removed by 4 
gasoline treatments is accepted as the total amount contained in the samples and is used as a basis, because 
the per cent of difference between t lie grease removed by the third and by the fourth treatment is shown to 
be negligible, the average being only 0.3. 

2 The weight of grease removed is determined by the subtraction of the conditioned weight of degreased 
wool from the conditioned weight of greasy wool. It is shown in the previous discussion that not aU mois- 
tnre is removed by conditioning. However, variation in moisture content of conditioned wool is not suffi- 
cient to cause appreciable error. Consequently slight errors caused by overweight due to moisture in the 
degreased samples occur at times but are not sufficient to aflect the value of the final results. 



The average results in Table 5 show that from the Kambouillet 
fleece samples the grease removed by one treatment was 15.04 per cent 
of the conditioned weight of raw wool; 17.31 by two; 18.11 by three; 
and 18.15 by four. The average results from the crossbred fleece 
samples were 12.09 per cent of grease removed by one treatment; 13.19 



DETERMINING GREASE AND DIRT IN WOOL. 



13 



by two; 14.78 by three; and 15.10 by four. This indicates that after 
three treatments of gasoline the remaining grease is not sufficient to 
cause any appreciable error, there being only 0.04 per cent removed 
by the fourth treatment from the Rambouillet samples and 0.32 
per cent from the crossbred. 

The results of three other runs of 20 samples each of Rambouillets 
and erossbreds (based on the results of Table 5, which show that three 
is the least number of treatments which can be used) show in Table 6 
the amount of grease removed by each extraction above the third 
until the samples are free from grease. 

Table 6. — Grease removed by gasoline treatments, conditioning after the third and after 

each succeeding treatment. 
RAMBOUILLET FLEECE SAMPLES. 



Sample No. 



Con- 
ditioned 
weight 
of raw 
wool. 
(grams) . 



801-.. . 


239.8 
233. 6 
242.4 
241.0 
235.7 
239.9 
237.4 
236.6 
238.6 
230. 4 
239. 3 
240.6 
239.1 
235.6 
2411. 
236.4 
237.5 
233.6 
236.6 
239.0 
239.5 
239.6 
242.9 
236.7 
239. 8 
244.2 
236.2 
240.4 
237. 1 
237.1 
239.2 
236.7 
234 5 


U. S.77... 


1303 


1305 


2058 


2080 


2141 


2151 


2268 .... 


2353 


235li 


2366 


2413 


2569 


26S6 


2724 


2753 


275s 


2910 


2911 


588 


1101 


1125 


1201 


1350 


13s7 


1850 


2360 


2410 


2434 


2470 


2471 


2582 


2643 


2.">4 2 


2666 


239.3 
239.2 
235.1 
235.3 
234. 6 
230.4 
239.5 
237.6 
231.4 
236 S 


2819 


2931 


2937 


2999 


3137 


594 


10S9 


1122 


1177 


1205 


235.3 


1336 


238.9 


1345 


242.2 
238.3 
239.9 


1630 


1823 


2068 


253.3 


2194 


23 S. 4 


2343 


240.3 


2548 


237.9 


'See footnote 2 under Table 5 





Cumulative weight 
of grease re- 
moved at treat- 
ment (grams). 



Third. Fourth. 



40.3 
35.9 
61.6 
42.4 
37.1 
45.1 
40.6 
34.6 
40.7 
37.6 
54.9 
42. 6 
49.6 
28.5 
40. S 
37.9 
27.9 
23.0 
35.2 
29.2 
44.3 
32.1 
42.3 
44.5 
51.7 
44.0 
34.7 
46.8 
40.5 
29.3 
34.2 
41.0 
28.1 
47.3 
37.3 
53.7 
26.1 
35.1 
28.5 
30.3 
29.7 
32.7 
30.0 
40.5 
33.2 
32.1 
45.9 
52.5 
63.5 
50.7 
40.4 
41.8 
35.7 



40.5 
135.6 
62.2 
42.7 
37.7 
45.4 
40.7 
34.6 

■ 40. 4 
'37.3 
' 54.5 

45.0 

'• 49. :, 

' 27.2 

41.9 

3S.1 

28.3 

24.7 

'35.1 

29.7 

45.4 

32.6 

4:!. 3 

46.5 

'■ ; 7 

4.-.. 1 

35.8 

48.0 

42. 2 

30.5 

35. 2 

41.3 

' 2S. 

47. S 

37.9 

54.0 

20. 2 

'35.0 

'28.4 

'30.2 

'29.6 

' 32. 5 

31.0 

40.9 

33.8 

32.8 

■ 45.7 
54.0 
63.8 
50.7 

'39.3 

' 41.6 

36.3 



Cumulative per 
cent of grease re- 
moved at treat- 
ment. 



Third. Fourth. 



16. M 
15.36 
25. 41 

17.59 
15.74 
18.79 
17.1 
14.62 
17.05 
15.91 
22.94 
17.71 
20. 74 
12.09 
17.00 
16.03 
11.74 
9. S4 
14.87 
12. 21 
18.49 
13. 39 
17.41 
IS. 80 
21.55 
IS. 01 
14.69 
19.46 

17. OS 
12. 35 
14.29 
17. 32 
11.9S 
18.81 
15.58 
22. 44 
11.10 
14.91 
12.14 
13.15 
12.40 
13.76 
12.96 
17.10 
14.11 
13.43 
IS. 95 
22.03 
26.46 
20.01 
16.94 
17.39 
15.01 



16.88 

' 15. 23 

25.66 

17.71 

15.99 

18.92 

17.14 

14.62 

' 16. 93 

' 15.77 

' 22. 77 

18.70 

' 20. 70 

l 11.54 

17.45 

16.11 

11.91 

10.57 

■ 14. S3 

12.42 

18.95 

13.61 

17. 82 

19.64 

22.39 

is. 40 

15.15 

19.96 

17.79 

12. 86 
14.71 
17. 44 

' 11.94 

15. 83 

22. 57 

11.14 

' 14. 87 

12.11 

13.11 

' 12. 35 

' 13.67 

13.39 

17.27 

14.36 

13. 72 
i 18.86 

22.66 
26.51 
20.01 
i 16.48 
i 17.31 
15.25 



Percent 
grease 
removed 
by fourth 
treat- 
ment. 



-0.07 
1-. 13 

.25 

.12 

.25 

.13 

.04 

.00 

' - .12 

i - .14 

l - .17 

.99 

i -.04 

■ -.55 

.45 
.08 
.17 
.73 
l -.04 
.21 
.4''. 
.22 
.41 
.84 
.s4 
.45 
. 41. 
.50 
.71 
.51 
.42 
.12 
l -.04 
.19 
.25 
.13 
.04 
i -.04 
1-.03 
1 -.04 

■ -.05 

■ -.09 

.43 
.17 
.25 
.29 

■ -.09 

.63 
.05 
.00 
i -.46 
' -.OS 
.24 



Per cent 
total 
grease 
removed 
by three 
treat- 
ments. 



99. 51 

■ 100. S4 

99.03 

99.29 

9S.41 

99.33 

99.75 

100.00 

l 100. 74 

l 100. SO 

i 100. 73 

94.66 

l 100. 20 

l 104. 77 

97.37 

99.47 

9S.5S 

93.11 

l 100. 28 

9S.31 

97.57 

9S.46 

97.69 

95.69 

96.27 

97.56 

96.92 

97.50 

95.97 

96.06 

97.15 

99.27 

i 100.35 

9S.95 

98.41 

99.44 

99.61 

l 100. 28 

l 100. 35 

l 100. 33 

i 100.33 

l 100.61 

96.77 

99.02 

98.22 

97.86 

i 100.43 

97.22 

99.84 

100.00 

i 102.79 

i 100. 4S 

98. 34 



14 



BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE. 



Table 6. — Grease removed by gasoline treatments, conditioning after the third and after 

each succeeding treatrm nt — Continued. 

RAMBOCILLET FLEECE SAMPLES— Continued. 



Sample No. 



Con- 
ditioned 

weight 
of raw- 
wool 
(grams) 



Cumulative weight 

of grease re- 
moved at. treat- 
ment (grams). 



Third. 



Fourth. 



Cumulative per 
cent of grease re- 
move! at treat- 
ment. 



Third. 



Fourth. 



Percent 

removed 
by fourth 
treat- 
ment. 



Per cent 
total 
grease 
removed 
by three 
treat- 
ments. 



2713 

2751 

2956 

3015 

3073 

33-E 

Average 



237.0 

237.2 
235.7 
227. 5 
241.5 
244. 2 
246. 8 



3H.5 
32.9 
41.7 
37. 5 
34.6 
16. 3 
l., 6 



39.6 
32.9 
42.2 
37.5 
54.7 
' 45.9 
46.6 



16. 66 

13. X7 
17.69 
16. 4S 
22. 61 
IS. 95 
18.88 



16.71 
13.87 
17.911 
16. 4S 
22. 65 
i 18.79 
18.88 



0.05 
.00 
.21 
.00 

.1)4 

-.16 

.00 



23S. ;, 



39. v 



in. 2 



16 66 



16. Si 



i K'l.-SBRED FLEEl E SAMPL1 S. 



99.74 
lflO.OO 

98.81 
100.00 

99.81 

i 100.87 

100.00 



98.99 



Lcn. 397 

Lcn. 507 

Bmy. 4s 

A-24 

A 18. 

A-220 

A-295 

A-4S0 

B-335 

B-355 

B-545 

B-565 

C-144 

C 157 

D-26 

E-37 

E-167 

0-46 

0-96 

C. S. 32 

Lcn. 439 

Lcn. 467 

Lcn. 472 

Lcn. 475 

('1:1.61 

A-5 

A-70 

B-5 

B-352 

B-409 

B-451 

B-579 

C-58 

C-159 

C-191 

D-8 

E-42 

E-165 

O-106 

U. S.7 

Lcn. 160 

Lcn. 388 .... 

Lcn. 498 

O-70 

Cla. 54 

Cla. 138 

A-68 

A -423 

A-487 

B-28 

B-626 

B-821 

Lst. 21 

D-1S 

D-24 

O-160 

E-21 

E-38 

U.S. 37 

U.S. 159 

Average 



238.4 
239.8 
245.0 
246.5 
■237.1 
239.4 
244. S 
230.2 
236.9 
216.9 
234.0 
220.0 
240.5 
241.7 
238.0 
236.4 
235.3 
236.6 
249.4 
253.2 
255.8 
240.7 
237.8 
251.9 
237.6 
250.0 
294.9 
251. s 
239.7 
181.4 
234.2 
260.1 
239.6 
238.0 
242.7 
241.5 
237.7 
250.4 
235.5 
238.1 
240.8 
239.4 
245.3 
244.9 
261.3 
239.6 
250.0 
254.0 
235.3 
253.6 
239.3 
234.9 
235.5 
235.1 
240.1 
248.9 
228.2 
236.4 
248.5 
228.0 



241.0 



40.8 
53.4 
30.9 

47.3 

35.1 
25.0 
36 3 
28. 8 
37.2 

29 7 
22.6 
33.6 
23. ; 
26 8 
41.7 


■j.; i 
30.6 
52. 4 

26, 7 
22. 8 
28.9 

27, s 
16.4 
32 2 
37.5 
33.1 
34.1 
26.3 
36.3 
31.6 
27.3 
28.7 
23.3 
19.3 
30.1 
16.7 
22. 2 
39.3 

30 3 
24.6 
35.1 
33.1 
29.9 
35 9 
32 6 
28 v 
26. 9 
28.6 
27.1 
22. 2 
2L9 
26.11 

31 9 
22 1 

54.6 
-1'.' 6 

n i. 



' 40. 7 
53.7 
32.1 
49.4 
33.7 
36.0 

'24.8 
37.0 
29.0 

■37.1 
29.7 
23.0 
34.2 
24.4 
26 8 
45.4 
24.5 
23.4 
30.7 
52.7 
26: 7 
22 8 
30.0 
27.9 
17.7 
32.2 

■ 37.4 
33.5 
31.1 

26.7 
36.9 

31.6 

28.3 
30.6 
25.3 
19.7 
30.8 
17.5 
22.9 
39.6 
30.5 
25. 1 

33.8 
30.1 
37.2 
33.2 
28. S 
28.8 
29.9 
28.9 
22.2 
•21.6 
27. 1 
32.4 
24.7 
36.6 
55.4 
50.2 
16 4 



31.5 



17.11 
22.26 
12.61 
19.18 
14.17 
14.66 
10.21 
15. 76 
12.15 
17.15 
12. 69 
111.27 
13 H7 

9.81 
11.26 
17.63 

9.77 

9.89 
12.26 
20. 69 
10. 43 

9.47 
12.15 
11.03 

6.90 
12.88 
12.71 
12.99 
14.22 
14.49 
15.49 
12. 14 
11.39 
12.05 

9.60 

7.99 
12.66 

6.66 

9.42 
16,51 
12.58 
10.27 
14.31 
13. 51 
11.44 
14.98 
13.04 
11.33 
11.43 
11.27 
11.32 

9.45 

9.29 
11.05 
13.28 

VS7 
15.60 
23.09 
19.95 

6.40 



12.77 



i 17.117 
22.39 
13.10 
20.04 
14.21 
15.03 
i 10. 13 
16.07 
12.24 
i 17.10 
12.69 
10. 15 
14.22 
10.09 
11.26 
19.20 
10.41 

'I VI 
12.31 
20.81 
111.43 

9.47 
12.61 
11.07 

7.44 
12.88 
l 12.68 
13.14 
11.22 
14.71 
15.75 
12.14 
II M 
12.85 
10. 42 

8.15 
12.95 

6.98 

9. 72 
16.63 
12.66 
10.48 
14.34 
13.80 
11.51 
15.52 
13.28 
11.33 
12.23 
11.79 
12. 07 

9.45 
'9.17 
11.52 
13.49 

9.92 
16.03 
23.43 
20.20 

7.19 



13.05 



-0.04 
.13 
.49 
.86 
.04 
.37 

1-.08 
.31 
.09 

1-.05 
.00 
.28 
.25 
.28 
.00 
1.57 
.64 
.00 
.05 
.12 
.00 
.00 
.46 
.114 
.54 
mi 

| 03 
.15 
.00 
.22 : 
. 26 
.mi 
.42 
.80 
.82 
.16 
.29 
.32 
.30 
.12 
.08 
.21 
.03 
.29 
.07 
.54 
.24 
.00 
.80 
.52 
.75 
.00 

1— .12 
.47 
.21 
1.05 
.43 
.34 
.25 
.79 ; 



i llin.24 
99.44 
96.26 
95. 74 
99.70 
97.50 

! 1UII Sll 
'.IS. 11 

99.31 
i 100. 26 

100.00 
'.Is. 21. 
98.24 
97.13 

100.00 
91.85 
93. S7 

100.00 
99.67 
99.43 

100.00 

100.00 
96.33 
99.64 
92.65 

100.00 

i 100.26 

98.81 

100.00 
98 50 
98. 37 

100.00 
96.46 
93.79 
92.09 
97.96 
97.72 
95.42 
96.94 
99.24 
99.34 
98.01 
99.71 
97.92 
99.33 
96.51 
98.19 

100.00 
93.40 
95.65 
93.77 

100.00 
i 101.38 
95.94 
98.45 
89. 17 
97.26 
98.55 
'.K Ml 
89.02 



.28 



97. S4 



>See footnote - under Table 5. 



DETERMINING GREASE AND DIRT IN WOOL. 15 

Table 6 shows that the grease removed from the 60 Rambouillet 
fleece samples by the first three extractions averaged 16.66 per cent 
of the conditioned weight of the raw wool, while at the fourth extrac- 
tion the per' cent averaged 16.83, or 0.17 per cent removed by the 
fourth treatment. From the 60 crossbred samples an average of 
12.77 per cent of grease was removed by the first three treatments, 
and 13.05 per cent by four, or 0.28 per cent by the fourth treatment. 
From the extremely small amount of grease removed by the fourth 
extraction in each case, it is assumed that the per cent of grease 
extracted by the four treatments shows the total quantity of grease 
contained in the samples, and that the per cent removed by the 
fourth is negligible. Using the figures obtained from the four extrac- 
tions as the total amount of grease, and therefore as a basis for 
calculation, Table 6 shows that 98.99 per cent of the total grease was 
removed by three extractions from the Rambouillet samples and 
97.84 per cent from the crossbred. Since these tests show that only 
a negligible quantity of grease is removed by the fourth extraction, 
it has been decided to use three gasoline treatments in the scouring 
process. 

DETERMINING WEIGHT OF DIRT. 

Before the third conditioning of the wool in the oven, it is necessary 
to remove all the dirt in order to obtain the clean-wool weight. A 
part of the dirt is of course removed with the grease by the gasoline 
treatments. This is caught by the filter papers and kept with the 
samples until they are ready to be washed in the tub, when the dirty 
filter papers are thrown away. The rest of the dirt is removed by 
means of soap and water in the tub, about half a pound of rteutral 
soap proving to be sufficient for the 150 gallons of water used. The 
temperature of the water is kept at 40° to 45° C, as trials showed that 
temperature to be sufficient for the removal of the dirt, without being 
hot enough to felt the wool. After the wool has been washed, rinsed, 
and dried in blower and oven, the clean weight of the wool is taken. 
The weight of dirt is determined by subtracting the weight of 
clean wool from the weight of degreased wool before the removal of 
the dirt. 

WEEKLY WORKING SCHEDULE. 

In order to scour all the samples sent to the laboratory each year, 
it is necessary to complete 60 each week. Owing to the fact that in 
the process each set of samples must dry after the various treat- 
ments — three, hours in the conditioning oven at three different times, 
about three hours between each of the three gasoline treatments, and 
eight hours in the blower dryer — it is evident that considerable time 
elapses between the beginning and the completion of the scouring of 
each run of samples. For example, a run started on Monday will be 
completed on Friday. 



16 



BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE. 



The laboratory is equipped to handle only 20 samples at a time. 
Consequently it is important that the runs be arranged in such way 
that they do not conflict in the use of the apparatus, and that all runs 
will be handled in the same way as nearly as possible. Therefore, in 
order to obtain uniformity of treatment and the largest possible 
weekly output, the following schedule has been worked out. It is so 




Fig. 5.— Washing apparatus. The empty washing baskets arc shown in the first tub and the washing 
baskets filled with wool in the second tub. When this apparatus is in operation the washing baskets 
rise, move from end to end, and fall. Not e the holes in the partition between the first and second tubs. 
Water is allowed to rise almost to these holes and is then shut off. In case of an overflowlhe holes pre- 
vent flooding the top. The water is heated by steam pipes in the bottom of each tub. At the right of 
A is the electric switch button and the motor, B, that drives the washing machinery. The ordinary 
clothes wringer shown in the foreground is used for wringing water from washed, rinsed wool samples. 
The air pipe, C, conducts air into tank, D, of the blower-dryer. The heated air returns through the 
upper part of the blower-dryer, where the baskets of wool are placed for drying, and the air passes out 
of the dryer through the pipe shown at E. 

arranged that it operates in weekly cycles (the work of each day of 
the week being the same as that of the preceding week). This 
schedule also has the advantage of rendering possible the picking up 
of the threads of the process, without delay, in case of change in 
individual operators in the laboratory. 

The different steps outlined below are explained in detail on 
pages 2, 3, and 4. 



DETERMINING GREASE AND DIRT IN WOOL. 



17 



Weekly schedule of work at Bureau of Animal Industry Wool Laboratory, Beltsville, Md. 



A.M. 


9.00 


9.25 


10.00 


10.15 


P.M. 


1.00 


4.00 


4.45 



Place baskets Sl-100 in oven empty. 
Weigh baskets 81-100. Take 

from oven, fill with new wool. 
Put 81-100 in oven for three hours. 
Fold and weigh filter papers. 

Weigh baskets Sl-100. 

Put gasoline on baskets 81-100. 

Filter. 

Blower on all day. 

TUESDAY. 



A. M 
9.00 
9.20 
9.25 



Place baskets 21—40 in oven empty. 
Distill gasoline. 

Weigh baskets 21-40. Take from 
oven, fill with new wool. 
10.00 Place baskets 41-60 (clean wool left 



A. M. 
9.00 
9.20 
9.25 

10.00 
10.30 
11.15 
P. M. 

12.00 
1.00 

1.15 
1.30 
2.00 
3.30 
4.15 
4.30 



THURSDAY. 

Place baskets 61-80 in oven empty. 

Distill gasoline. 

Weigh baskets 61-S0. Take from 

oven, put in new wool. 
Place 61-80 in oven for three hours. 
Put gasoline on 21-40. 
Filter. 

Place 21-40 in blower for 1\ hours. 

Weigh 61-80. 

Distill gasoline. 

Place 21-10 in oven three hours. 

Fold and weigh filter papers. 

Put gasoline on 61-80. 

Filter. 

Weigh baskets 21-40. 

Blower on all dav. 



from preceding week) n 


l oven ior 


FRIDAY. 


three hours. 




A. M. 


11.00 Put gasoline on 81-100. 




9.20 Distill gasoline. 


11.45 Filter. 




10.00 Wash 21-40. 


P.M. 




11.00 Put gasoline on 61-80. 


1.00 Weigh baskets 41-60. 




11.45 Filter. 


1.15 Distill gasoline. 




P. M. 


1.30 Place baskets 21-40 in 


oven for 


1.30 Place 81-100 in oven for three hours 


three hours. 




1.30 Distill gasoline. 


3.30 Put gasoline on 81-100. 




3.30 Put gasoline on 61-80. 


4.15 Filter. 




4.15 Filter. 


4.30 Weigh 21-40. 




4.30 Weigh 81-100. 

Blower on from 12 to 5 o'clock. 


WEDNESDAY. 






A. M. 




SATURDAY. 


9.20 Distill gasoline. 




A. M. 


10.00 Place baskets 81-100 in 


oven for 


9.20 Distill gasoline. 


three hours. 




10.00 Place 61-80 in oven for three hours. 


10.15 Fold and weigh filter papers. 


P. M. 


11.00 Put gasoline on 21-40. 




1.00 Weigh 61-80. 


11.45 Filter. 




1.30 Place 21-40 in oven for three hours 


P.M. 




1.30 Wash 61-80 in tub. 


1.00 Weigh baskets 81-100. 




4.30 Weigh 21-10. 


1.30 Wash 81-100. 




Blower on till noon. 


2.30 Distill gasoline. 






4.00 Put gasoline on 21-40. 






4.45 Filter. 







18 



BULLETIN 1100, U. S. DEPARTMENT OF AGRICULTURE. 



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DETERMINING GREASE AND HUM' IN WOOL. 



19 



EXPLANATION OF WOOL-SCOURING DATA SHEET. 

Actual weights taken in the laboratory are recorded as shown 
in Table 7 in columns a, b, d, e, and h. All weights of wool shown on 
data sheet are conditioned weights. The others are filled in from 
calculations made from a, b, d, e, and h. The following formulas 
show the calculation used to obtain the figures of each column. 
a — b=c f— j=i 

d-(b+e)=f 100 i-i-c=l 

c—/=g 100 j^-c=m 

h-b = i 100g-=-j=n 

100 g+c=k 100 i-+-j=o 

or: 




Fig. 6. — Baskets of wool. A, raw wool before scouring. B, decreased wool, dirt remaining. C,clean, 
scoured wool, free from grease and dirt. 

The weight of basket (b) subtracted from the conditioned weight 
of sample and basket (a) gives the conditioned weight of greasy wool 
(c). 

The weight of basket (b) and weight of filter paper (e) subtracted 
from the conditioned weight of wool, filter paper, and basket after 
extraction id) gives the conditioned weight of wool and dirt after 
extraction (f). 

The conditioned weight of greasy wool (c) minus the conditioned 
weight of wool and dirt after extraction (/') ^ives the weight of grease 



20 BULLETIN 1100, U. S. DEPARTMENT OF AG 015 870 917 A 

The conditioned weight of wool and basket after washing (h) 
minus the weight of basket (b) gives the conditioned weight of clean 
wool (j). 

The weight of grease (</) divided by the weight of greasy wool (c) 
gives the per cent of grease in the sample (k). 

The conditioned weight of wool and dirt after extraction (/) minus 
the conditioned weight of clean wool (;') gives the weight of dirt (i). 

The weight of dirt (i) X 100 divided by the conditioned weight 
of greasy sample (c) gives the per cent of dirt (?) . 

The weight of clean wool (j) X 100 divided by the conditioned 
weight of the greasy sample (c) gives the per cent of clean wool (m). 

The weight of grease (g) X 100 divided by the conditioned weight 
of clean wool (j) gives the grease index (n). 

The weight of dirt (i) X 100 divided by the conditioned weight 
of clean wool (j) gives the dirt index (o). 

SUMMARY. 

Before the scouring process, all samples of wool are brought to a 
constant-moisture content. 

In the moisture experiments here reported, 20 per cent moisture 
was the largest percentage for any of the samples used. 

When there is no more than 20 per cent moisture in air-dry samples, 
it has not been found necessary to condition them longer than three 
hours nor at a temperature higher than 50° C. 

Grease is removed by washing the samples in gasoline, which is 
drained off through filter papers in order to retain all foreign matter. 

Three gasoline treatments are used in degreasing the wool, since 
it has been found that only 0.17 per cent of grease remains in Ram- 
bouillet wool after three treatments, and 0.28 per cent in crossbred 
wool. 

Dirt is removed from the samples by means of soap and water. 
A temperature of 40° to 45° C. is used for the water, as trials show 
that this is sufficient to remove the dirt, without being hot enough 
to felt the wool. 



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